This is a revised application for the Psychosocial/Qualitative Assessment Core of the HIV Center. Research on behavioral change to reduce the risk of HIV infection has been central to the Center's work during its first ten years. In order to successfully design, develop, and evaluate the effects of behavioral interventions and prevention programs, psychosocial assessment that draws on both quantitative and, increasingly, qualitative research methods has been a high priority, and the HIV Center has emerged as one of the leading research center sin the country for development of innovative approaches to the study of HIV/AIDS. In order to coordinate and systematize work in these areas, a Psychosocial/Qualitative Assessment Core was created and played a key role in the development of the Center's research activities over the past five years. To further extent the HIV Center's leadership in this are, this Core has been maintained in the current renewal proposal, and a plan has been developed for a range of Core activities over the coming five-year period. The Core has three primary aims: 1. To serve as a central advisory resource on the development of methodologically rigorous, theory-driven, culturally sensitive procedures for qualitative assessment, quantitative assessment, and process evaluation as part of research projects developed through the HIV Center. 2. To develop and oversee procedures for quality control and to coordinate sharing of information, procedures, and operational criteria across projects on assessment issues. 3. To develop a range of training and capacity-building activities for HIV investigators and others to strengthen their ability to design and carry out both qualitative psychosocial research on HIV/AIDS prevention. 4. To assist HIV Center investigators and other by functioning as a nucleus for analysis of the theoretical and methodological issues with psychosocial assessment as part of HIV/AIDS prevention science. Thus, the Psychosocial/Qualitative Assessment Core will build on the history of HIV Center research, and its work will help to ensure that the Center continues to make the greatest possible contribution to the development of effective social and behavioral assessment and evaluation procedures as part of HIV/AIDS prevention science in the future.